1. Field of Invention
The present invention relates generally to storage area networks and devices, and relates more particularly to N port identifier virtualization (NPIV) proxy gateway (NPG) mode.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
As information handling systems provide increasingly more central and critical operations in modem society, some standards have developed related to network storage. One example is Fibre Channel (FC). Fibre channel is a high speed network technology used to connect computer data storage. Fibre channel is often used in connecting Storage Area Networks (SAN's) in enterprise storage.
A switched fabric topology can be used with fibre channel. In a switched fabric topology all ports are connected to fibre channel switches. Ports can be any entity that communicates over the network.
Node Port Identifier Virtualization (NPIV) is a fibre channel feature whereby multiple fibre channel node port IDs can share a single physical node port. This allows multiple fibre channel initiators to occupy a single physical port.
Prior art solutions for configuring per end node port (enode) port is limited to 32 or 64 sessions in an Node Port Identifier Virtualization (NPIV) Proxy Gateway (NPG/FSB). This limit is present due to the Access Control List (ACL) regions, which is the secure link from the enode to the storage network to implement fip-snooping capability in a secure way. Therefore, in the prior art the limit of 32 or 64 can be reached in NPG mode.
FIG. 1 shows a prior art embodiment of a system 100 using NPIV and a login sequence using NPIV. FIG. 1 shows a Converged Network Adapter (CNA) 105 communicates with an input-output accelerator (IOA) 110. IOA 110 communicates with an FC switch 115. A prior art login sequence using NPIV, includes communication between the IOA 110 and FC Switch 115, including communication 120, 125, 135, 140, 155, and 160. Prior art login sequence also shows communication between the CNA 105 and the IOA 110 including communication 130, 145, 155, and 165. Figure shows IOA 110 sends FC switch 115 a fabric login (FLOGI) 120, FC Switch 115 sends to IOA 110 a fabric login accept (FLOGI_ACC) 125. CNA 105 sends to IOA 110 an FLOGI 130. IOA 110 sends to FC switch 115 fabric discovery (FDISC) 135. FC Switch 115 sends to IOA 110 fabric discovery accept (FDISC_ACC) 140. IOA 110 sends to CNA 105 FLOGI_ACC 145. CNA 105 sends to IOA 110 FDISC 150. IOA 110 sends to FC switch 115 FDISC 155. FC switch sends to IOA FDISC_ACC 160. IOA 110 sends to CNA 105 FDISC_ACC 165.
The 32 or 64 session limit does not guarantee per port logins, but depends on the utilized and available ACL regions. There is no way to intimate the Converged Network Adapter (CNA) to stop further Fabric Discovery (FDISC) retries, if the CNA does more logins than the configured enode limit or if the ACL region is elapsed.
FIG. 2 shows a block diagram of a prior art login sequence 200 including continuous FDISC retries 210 and 230, 240, 250, 260, 270, and 280. It also shows ACL limit reached or Max enode session limit reached hence packet dropped 220. It shows depicts the continuous FDISC retries.
This continuous FDSIC re-trials (˜2 sec) make use of Central Processing Unit (CPU) cycles of both the CNA and NPG/IOA. The NPG/IOA CPU processes the Virtual Link initial request and then drops it as the limit is already reached, leading to extra CPU processing at the NPG/IOA side. Also, there is no intimation to the CNA for failure of response of FDSIC request and hence the CNA keeps trying leading to CNA CPU consumption. If the ACL limit is reached the sessions could flap before stabilizing.
One disadvantage of the prior art system is that there is no way to stop the CNA from making further FDISC requests if the ACL limit has been reached.
Another disadvantage of the prior art system is that CPU consumption is used both at the CNA and the NPG/IOA.
Accordingly, what is needed are systems and methods that can achieve NPIV login limit intimation to the CNA in NPG mode.